Fluoroalkylated liquid-crystal compounds, liquid-crystal compositions, and liquid-crystal display elements

ABSTRACT

The present invention provides liquid crystalline compounds having a very high voltage holding ratio, very little variation of these properties depending on temperature, high Δn, and good compatibility in the other liquid crystal materials particularly under a low temperature, liquid crystal compositions containing these crystalline compounds, and liquid crystal display devices constituted by using the liquid crystal compositions. The liquid crystalline compounds are represented by general formula (1):                    
     wherein R represents an alkyl, alkoxy or alkoxyalkyl group of 2-20 carbon atoms, and in each group, any 1-3 hydrogen atoms may be replaced by fluorine atoms; X shows an halogen atom or an alkyl group of 1-20 carbon atoms, any methylene groups (—CH 2 —) not adjacent each other in the alkyl group may be replaced by oxygen atoms, and any one or more hydrogen atoms in the alkyl group may be replaced by fluorine atoms; Z 1 , Z 2  and Z 3 , each independently, represents —(CH 2 ) 2 —, —(CH 2 ) 4 —, —CH 2 O—, —OCH 2 —, —(CH 2 ) 3 O—, —O(CH 2 ) 3 — or a covalent bond; Y 1 -Y 16  each independently represent hydrogen atoms or fluorine atoms, but at least two represent fluorine atoms; m represents 0 or 1, and any atom constituting the compound may be replaced by an isotope thereof.

This application is a 371 of PCT/JP97/03404 filed Sep. 25, 1997.

TECHNICAL FIELD

The present invention relates to new liquid crystalline compounds andliquid crystal compositions, more particularly, it relates to liquidcrystalline compounds having alkyl groups, alkoxy groups and alkoxyalkylgroups, which are substituted by fluorines, liquid crystal compositionscontaining them, and liquid crystal display devices constituted by usingthe liquid crystal composition.

BACKGROUND ART

The liquid crystal display devices using the liquid crystalline compound(in this description, the term of a liquid crystalline compound is usedas a generic term for a compound exhibiting a liquid crystal phase or acompound not exhibiting a liquid crystal phase but useful as aconstituent of a liquid crystal composition) are broadly used indisplays of clocks, watches, electronic calculators, word processors andthe like.

Lately, much research has been conducted for a TFT type display havingproperties such as a high contrast and a wide viewing angle. Liquidcrystal compositions for TFT need physical properties, such as a highvoltage holding ratio, low threshold voltage (Vth), little variation ofthese properties depending on temperature, broad temperature range ofliquid crystal phase and low viscosity. Further, the compositions havinga high optical anisotropy (Δn) are useful for improving the responsespeed.

For these reasons, compounds of fluorine types are preferably used, asdescribed in (1) Japanese Patent Publication 63-13411, (2) JapanesePatent Publication 63-44132, (3) Japanese Patent Laid-open 2-233626, (4)Japanese Patent Laid-open 2-501311, (5) Japanese Patent Laid-open3-500413 and (6) DE4301700, many synthesis methods and researches havebeen done.

DISCLOSURE OF INVENTION

The present invention aims to provide liquid crystalline compoundshaving 1) a very high voltage holding ratio, 2) very little variation ofthese properties depending on temperature, 3) high Δn, and 4) goodcompatibility with other liquid crystal materials particularly under alow temperature, liquid crystal compositions containing thesecrystalline compounds, and liquid crystal display devices constituted byusing the liquid crystal compositions.

The present inventors have earnestly studied to resolve the aboveproblems and have completed the studies by obtaining the liquidcrystalline compounds having the above properties. The compounds arerepresented by general formula (1);

wherein R represents an alkyl, alkoxy or alkoxyalkyl group of 2-20carbon atoms, and in each group, any 1-3 hydrogen atoms may be replacedby fluorine atoms; X shows a halogen atom or an alkyl group of 1-20carbon atoms, any methylene groups (—CH₂—) not adjacent each other inthe alkyl group may be replaced by oxygen atoms, and any one or morehydrogen atoms in the alkyl group may be replaced by fluorine atoms; Z₁,Z₂ and Z₃, each independently, represents —(CH₂)₂—, —(CH₂)₄—, —CH₂O—,—OCH₂—, —(CH₂)₃O—, —O(CH₂)₃— or a covalent bond; Y₁-Y₁₆ eachindependently represent hydrogen atoms or fluorine atoms, but at leasttwo represent fluorine atoms; m represents 0 or 1, and any atomconstituting the compound may be replaced by an isotope thereof.

A part of the compounds represented by general formula (1) are formallyincluded in the compounds having general formula described in the abovereferences (5) and (6). However, in these references, there is nodescription of data such as values of physical properties of thecompounds of the present invention, and definite or embodiedcharacteristics of these compounds, so that the present invention is notsuggested.

The compounds represented by general formula (1) can be classified asfollows.

In the following, R, X and Z₁-Z₃ have the same meaning as describedabove, P represents a 1,4-phenylene group in which any one or morehydrogen atoms may be replaced by fluorine atoms.

Compounds having 3 six-membered rings:

R-P-P-P-X  (1a)

R-P-Z₁-P-P-X  (1b)

R-P-P-Z₂-P-X  (1c)

R-P-Z₁-P-Z₂-P-X  (1d)

Compounds having 4 six-membered rings:

R-P-P-P-P-X  (1e)

R-P-Z₁-P-P-P-X  (1f)

R-P-P-Z₂-P-P-X  (1g)

R-P-P-P-Z₃-P-X  (1h)

R-P-Z₁-P-Z₂-P-P-X  (1i)

R-P-Z₁-P-P-Z₃-P-X  (1j)

R-P-P-Z₂-P-Z₃-P-X  (1k)

R-P-Z₁-P-Z₂-P-Z₃-P-X  (1l)

In these compounds, particularly, the compounds represented by formulae(1a)-(1c) and formulae (1e)-(1h) are preferably used for attaining theobjects of the present invention.

In these formulas, R is an alkyl, alkoxy or alkoxyalkyl group of 2-20carbon atoms, and in each group, any 1-3 hydrogen atoms may be replacedby fluorine atoms. And specifically, fluoroalkyl groups of straightchain such as 1-fluoroethyl, 2-fluoroethyl, 1-fluoropropyl,2-fluoropropyl, 3-fluoropropyl, 1-fluorobutyl, 2-fluorobutyl,3-fluorobutyl, 4-fluorobutyl, 1-fluoropentyl, 2-fluoropentyl,3-fluoropentyl, 4-fluoropentyl, 5-fluoropentyl, 6-fluorohexyl,7-fluoroheptyl, 10-fluorodecyl, 15-fluoropentadecyl, 20-fluoroicosyl,1,1-difluoroethyl, 1,2-difluoroethyl, 2,2-difluoroethyl,1,1-difluoropropyl, 2,2-difluoropropyl, 3,3-difluoropropyl,1,2-difluoropropyl, 1,3-difluoropropyl, 2,3-difluoropropyl,3,3-difluoropentyl, 5,5-difluoropentyl, 15,15-difluoropentadecyl,1,1,2-trifluoroethyl, 1,2,2-trifluoroethyl, 2,2,2-trifluoroethyl,1,1,2-trifluoropropyl, 1,1,3-trifluoropropyl, 1,2,2-trifluoropropyl,1,3,3-trifluoropropyl, 2,2,3-trifluoropropyl, 1,2,3-trifluoropropyl,3,3,5-trifluoropentyl and 16,17,17-trifluoroheptadecyl; and fluoroalkylgroups of branched chains such as 1-methyl-2-fluoroethyl,2-ethyl-3-fluoropropyl, 2-methyl-4-fluorobutyl,2,4-dimethyl-5-fluoropentyl, 3-ethyl-5-fluorohexyl and5-trifluoro-methyldecyl can be exemplified.

As the fluoroalkoxy groups, 1-fluoroethoxy, 2-fluoroethoxy,1-fluoropropoxy, 2-fluoropropoxy, 3-fluoropropoxy, 1-fluorobutoxy,2-fluorobutoxy, 3-fluorobutoxy, 4-fluorobutoxy, 1-fluoropentyloxy,2-fluoropentyloxy, 3-fluoropentyloxy, 4-fluoropentyloxy,5-fluoropentyloxy, 13-fluorotridecyloxy, 1,1-difluoroethoxy,2,2-difluoroethoxy, 1,2-difluoroethoxy, 1,1-difluoropropoxy,2,2-difluoropropoxy, 3,3-difluoropropoxy, 1,2-difluoropropoxy,1,3-difluoropropoxy, 1,1-difluorobutoxy, 2,2-difluorobutoxy,3,3-difluorobutoxy, 4,4-difluorobutoxy, 1,2-difluorobutoxy,1,3-difluorobutoxy, 1,4-difluorobutoxy, 2,3-difluorobutoxy,2,4-difluorobutoxy, 3,4-difluorobutoxy, 1,1-difluoropentyloxy,2,2-difluoropentyloxy, 3,3-difluoropentyloxy, 4,4-difluoropentyloxy,5,5-difluoropentyloxy, 1,2-difluoropentyloxy, 1,3-difluoropentyloxy,1,4-difluoropentyloxy, 1,5-difluoropentyloxy, 2,3-difluoropentyloxy,2,4-difluoropentyloxy, 2,5-difluoropentyloxy, 3,4-difluoropentyloxy,3,5-difluoropentyloxy, 4,5-difluoropentyloxy,16,16-difluorohexadecyloxy, 1,1,2-trifluoroethoxy,2,2,2-trifluoroethoxy, 1,1,2-trifluoropropoxy, 1,1,3-trifluoropropoxy,1,2,2-trifluoropropoxy, 1,3,3-trifluoropropoxy, 2,2,3-trifluoropropxy,1,2,3-trifluoropropxy, 3,3,3-trifluoropropxy, 2,4,4-trifluorobutoxy,3,4,4-trifluorobutoxy, 4,4,4-trifluorobutoxy and11,11,11-trifluoroundecyloxy can be exemplified.

As the alkoxy alkyl groups replaced by fluorines, fluoromethoxy methyl,1-fluoro-1-methoxymethyl, (1-fluoroethoxy)methyl, (2-fluoroethoxy)methyl, 1-fluoro-1-ethoxymethyl, (1-fluoropropoxy)methyl,(2-fluoropropoxy) methyl, (3-fluoropropoxy)methyl,1-fluoro-1-propoxymethyl, (1-fluorobutoxy) methyl,(2-fluorobutoxy)methyl, (3-fluorobutoxy)methyl, (4-fluorobutoxy) methyl,1-fluoro-1-butoxymethyl, 1-(fluoromethoxy)ethyl, 2-(fluoromethoxy)ethyl, 1-fluoro-2-methoxyethyl, 2-(1-fluoroethoxy)ethyl,2-(2-fluoroethoxy)ethyl, 2-(1-fluoropropoxy)ethyl, 2-(2-fluoropropoxy)ethyl, 2-(3-fluoropropoxy)ethyl, 2-(fluoromethoxy)propyl,3-(fluoro-methoxy)propyl, 2-(1-fluoroethoxy) propyl,3-(1-fluoroethoxy)propyl, 3-(2-fluoroethoxy)propyl,3-(3-fluoroethoxy)propyl, (difluoro-methoxy) methyl,1-fluoro-1-(fluoromethoxy)methyl, (1,1-difluoroethoxy)methyl,(1,2-difluoroethoxy)methyl, (2,2-difluoroethoxy)methyl,(1,1-difluoropropoxy)methyl, (2,2-difluoropropoxy)methyl, (3,3-difluoropropoxy)methyl, (1,2-difluoropropoxy)methyl,(1,3-difluoropropoxy)methyl, (2,3-difluoro-propoxy)methyl,2-(difluoromethoxy)ethyl, 2-(1,1-difluoroethoxy)ethyl,2-(2,2-difluoroethoxy)ethyl, 2-(1,2-difluoroethoxy)ethyl,2-(1,1-difluoropropoxy)ethyl, 2-(2,2-difluoropropoxy)ethyl,2-(3,3-difluoro-propoxy)ethyl, 2-(1,2-difluoropropoxy)ethyl,2-(1,3-difluoropropoxy)ethyl, 2-(2,3-difluoropropoxy)ethyl,2-(4,4-difluorobutoxy)ethyl, 3-(difluoro-methoxy)propyl,3-(2,2-difluoroethoxy)propyl, 3-(1,2-difluoroethoxy) propyl,3-(2,2-difluoropropoxy) propyl, 3-(3,3-difluoropropoxy)propyl,4-(difluoromethoxy)butyl, 4-(4,4-difluorobutoxy)butyl,5-(difluoromethoxy)pentyl, (trifluoromethoxy)methyl,(1,1,2-trifluoroethoxy)methyl, (1,2,2-trifluoroethoxy)methyl,(2,2,2-trifluoroethoxy)methyl, (2,2,3-trifluoropropoxy)methyl,(3,3,3-trifluoropropoxy)methyl, (4,4,4-trifluorobutoxy)methyl,(5,5,5-trifluoropentyloxy)methyl, 2-(trifluoro-methoxy)ethyl,(2,2,2-trifluoroethoxy)ethyl, (3,3,3-trifluoropropoxy)-ethyl,(4,4,4-trifluorobutoxy)ethyl, (5,5,5-trifluoropentyloxy)ethyl,(2,2,2-trifluoroethoxy)propyl, 3-(trifluoromethoxy)propyl,(3,3,3-trifluoropropoxy)propyl, (4,4,4-trifluorobutoxy)propyl,(5,5,5-trifluoropentyloxy)propyl, 4-(trifluoromethoxy)butyl,(2,2,2-trifluoro-oethoxy)butyl, (3,3,3-trifluoropropoxy)butyl,(4,4,4-trifluorobutoxy) butyl, (5,5,5-trifluoropentyloxy)butyl,5-(trifluoromethoxy)pentyl, (2,2,2-trifluoroethoxy)pentyl,(3,3,3-trifluoropropoxy)pentyl, (4,4,4-trifluorobutoxy)pentyl,(5,5,5-trifluoropentyloxy)pentyl can be exemplified. Moreover, in theabove R, the groups having the branched chains may be optically activegroups, and when R is the optically active group, the compound is usefulas a chiral dopant.

The number of fluorine atoms in R of the group is selected from anynumber of 1-3, preferably 1 or 2, because as the number of the fluorineatoms increases, the viscosity increases to some degree, and Δε etendsto decrease.

X is a halogen atom or an alkyl group of 1-20 carbon atoms, concretely,it is Br, Cl, F, I, —CF₃, —CF₂H, —CFH₂, —OCF₃, —OCF₂H, and the samemonovalent group as the above R.

In general formula (1), Z₁, Z₂ and Z₃, each independently, represents—(CH₂)₂—, —(CH₂)₄—, —CH₂O—, —OCH₂—, —(CH₂)₃O—, —O(CH₂)₃— or a covalentbond, preferably, it represents —(CH₂)₂—, —CH₂O—, —OCH₂— or a covalentbond.

The compounds wherein m is 0 show a liquid crystal phase (or a meltingpoint) at a relatively middle temperature, and the compounds wherein mis 1 show a high transition temperature of an isotropic phase (or amelting point).

When X is a strong electrophilic group such as a halogen atom, CF₃ orthe like, it shows very high positive Δε and very low threshold voltage.

Y₁-Y₁₆ are each independently selected from hydrogen atoms or fluorineatoms. As the number of the fluorine atoms increases, the viscositytends to increase, and Δε can be higher and then the compatibility isimproved.

The compound having an atom replaced by an isotope in the molecular isalso preferable because it shows similar physical properties.

By suitably selecting these substituted groups and bond groups,compounds having desired physical properties can be obtained.

Although the liquid crystalline compounds of the present inventionrepresented by general formula (1)may be prepared by a method of commonorganic synthesis, as an example, the compounds may be easily preparedby the following method.

wherein R, X, Y₁-Y₁₆, Z₁, Z₃ and m have the same meaning as describedabove, Xa and Xb are halogen atoms (particularly, bromine or iodine), nis 1 or 2, and p is 1 or 3.

Namely, as shown in scheme 1, in mixed solvent of three ingredients;toluene or xylene, alcohol such as ethanol, and water; compound (4) andcompound (5) can be reacted in the presence of a base such as K₂CO₃ orNa₂CO₃ and a catalyst such as carbon-carried palladium (Pd—C), Pd(PPh₃)₄or PdCl₂(PPh₃)₂ to produce an embodied compound (1) of the presentinvention. Further, as shown in scheme 2, after reacting compound (4)with a lithium compound such as n-BuLi or sec-BuLi and a zinc compoundsuch as ZnCl₂ or ZnBr₂, the reactant may be reacted with compound (6) toobtain the above compound (1).

As shown in scheme 3, after reacting compound (7) with Li, by reactingthe compound with a zinc compound and compound (6), example compound (2)of the present invention can be prepred.

As shown in scheme 4, in the presence of a base such as sodium amide (J.B. Right et al., Journal of the American chemical Society, 70, 3098(1948)), potassium carbonate (W. T. Olson et al., Journal of theAmerican Chemical Society, 69, 2451(1947)), triethylamine (R. L. Merkeret al., The Journal of Organic Chemistry, 26, 5180 (1961)), sodiumhydroxide (C. Wilkins, Synthesis, 1973, 156), potassium hydroxide (J.Rebek et al., The Journal of Organic Chemistry, 44, 1485 (1979)), bariumhydroxide (Kawabe et al., The Journal of Organic Chemistry, 37, 4210(1972)) or sodium hydride (C. J. Stark, Tetrahedron Letters, 22, 2089(1981), K. Takai et al., Tetrahedron Letters, 21, 1657 (1980)), in asolvent such as dimethylsulfoxide, dimethylformamide,1,2-dimethoxyethane, tetrahydrofuran, hexamethylphosphoric triamide ortoluene, compound (8) can be reacted with compound (9) to obtaincompound example (3) of the present invention.

As a method for introducing afluorine into group R, for example, thefollowing method can be indicated.

wherein X and Xa have the same meaning as described above, q shows aninteger of 2-20. In the above schemes 5-10, A₁ can be one of thefollowing groups.

wherein Y₁-Y₁₆, Z₁-Z₃ and m have the same meaning as described above.

Namely, as shown in scheme 5, by using fluorinating agent such asdiethylaminosulfur trifluoride (DAST) (W. J. Middleton et al., TheJournal of Organic Chemistry, 40, 574 (1975), S. Rozen et al.,Tetrahedron Letters, 41, 111 (1985), M. Hudlicky, Organic Reactions, 35,513 (1988), P. A. Messina et al., Journal of Fluorine Chemistry, 42, 137(1989)), morpholinosulfur trifluoride (K. C. Mange et al., The Journalof Fluorine Chemistry, 43, 405 (1989)) or hexafluoropropene-diethylamine reagent (Ishikawa et al., Bulletin of theChemical Society of Japan, 52, (11), 3377 (1979)), compound (10) can befluorinated to obtain compound (11). Further, as shown in scheme 6,after conducting a Wittig reaction of compound (12) with a phosphoniumsalt, in the presence of a catalyst such as Raney nickel or Pd—C, thecompound can be reduced with hydrogen to obtain compound (11).

As shown in scheme 7, compound (14) can be fluorinated with DAST toprepare compound (15).

As shown in scheme 8, compound (16) can be reacted with sodiumtrifluoroacetate/copper iodide (I) (G. E. Carr et al., Journal of thechemical Society Perkin Trans Actions I, 921 (1988) or methylfluorosulphonyl difluoroacetate/copper iodide (I) (Q. Y. Chen et al.,Journal of the Chemical Society Chemical Communications, 705 (1989)) toobtain compound (17).

As shown in scheme 9, compound (18) can be reacted withchlorodifluoromethane/sodium hydroxide (Japanese Patent Laid-open No.3-500413) to obtain compound (19). Otherwise, by a method of Chen et al.(The Journal of Fluorine Chemistry, 44, 433 (1989)), compound (19) maybe obtained.

As shown in scheme 10, compound (18) can be reacted by a method ofAlbert et al. (Synthetic Communications, 19, 547(1989)) to obtainxanthate (20) and then fluorinated by a method of Kurohoshi et al.(Tetrahedron Letters, 33, 29, 4173 (1992)) to obtain compound (21).

A substituted group of X can be easily obtained by using a raw materialhaving in advance the substituted group, or by introducing at anoptional step by the same method as in schemes 5-10.

The raw material, a halogen compound and a dihydroxyborane derivativecan be also produced by a common organic synthetic method , for example,these can be easily prepared by the following method.

wherein R, Y₁-Y₄ and Xa have the same meaning as described above.

Namely, as shown in scheme 11, by reaction of compound (22) with alithium compound such as n-BuLi and iodine or bromine, halogen compound(23) can be prepared.

As shown in scheme 12, after reacting compound (23), a Grignard reagent,which is prepared from magnesium, and a borane derivative such astrimethoxyborane or triisopropyloxyborane, the reactant can behydrolyzed with hydrochloric acid and the like to obtain dihydroxyboranederivative (24).

By combining the reactions described above taking the properties of thecompounds into consideration, the compounds of the present invention canbe prepared.

These exemplified reactions are known, and if necessary, the other knownreactions can be properly used.

The liquid crystalline compounds thus obtained have a very high voltageholding ratio, very little variation of these properties depending ontemperature and high Δn. These compounds can be easily mixed withseveral liquid crystal materials, and have good compatibility with theother liquid crystalline compounds under low temperature.

Moreover, these liquid crystalline compounds of the present inventionhave physically and chemically enough stability under general conditionsusing the liquid crystal display devices, and these are very excellentas a constituent of a nematic liquid crystal composition.

The compounds of the present invention can be preferably used as aconstituent of liquid crystal compositions for a display mode such asTN, STN, TFT or the like.

In the following, the liquid crystal compositions of the presentinvention are described. The liquid crystal compositions of the presentinvention preferably contain at least one compound represented bygeneral formula (1) at 0.1-99.9 % by weight so as to develop goodproperties.

More particularly, the liquid crystal composition provided by thepresent invention is obtained by mixing the first component containingat least one compound of general formula (1) and the compounds suitablyselected from the group of compounds represented by general formula(2)-(9) at an appropriate ratio.

wherein R₁ represents an alkyl group of 1-10 carbon atoms, anynonadjacent methylene groups in the said alkyl group may be substitutedby oxygen atoms or —CH═CH—, and any hydrogen atoms in the alkyl groupmay be substituted by fluorine atoms; X₁ represents a fluorine atom, achlorine atom, —OCF₃, —OCF₂H:, —CF₃, —CF₂H, —CFH₂, —OCF₂CF₂H or—OCF₂CFHCF₃; L₁ and L₂ independently represent a hydrogen atom or afluorine atom; Z₄ and Z₅ independently represent a 1,2-ethylene group,1,4-butylene group, —COO—, —CF₂O—, —OCF₂—, —CH═CH— or a covalent bond,ring B represents trans-1,4-cyclohexylene, 1,3-dioxane-2,5-diyl or1,4-phenylene whose hydrogen atoms may be substituted by fluorine atoms;ring C represents trans-1,4-cyclohexylene, or 1,4-phenylene whosehydrogen atoms may be substituted by fluorine atoms.

R₂ and R₃ independently represent an alkyl group of 1-10 carbon atoms,any nonadjacent methylene groups in the alkyl group may be substitutedby oxygen atoms or —CH═CH—, and any hydrogen atoms in the alkyl groupmay be substituted by fluorine atoms, X₂ represents —CN group or —C≡C—CNgroup; ring D represents trans-1,4-cyclohexylene, 1,4-phenylene,1,3-dioxane-2,5-diyl or pyrimidine-2,5-diyl; ring E representstrans-1,4-cyclohexylene, 1,4-phenylene whose hydrogen atoms may besubstituted by fluorine atoms, or pyrimidine-2,5-diyl; ring F representstrans-1,4-cyclohexylene or 1,4-phenylene; Z₆ represents a 1,2-ethylenegroup, —COO— or a covalent bond; L₃, L₄ and L₅ independently represent ahydrogen atom or a fluorine atom; b, c and d independently represent 0or 1;

R₄ and R₅ independently represent an alkyl group of carbon atoms of1-10, any nonadjacent methylene groups in the alkyl group may besubstituted by oxygen atoms or —CH═CH—, and any hydrogen atoms in thealkyl group may be substituted by fluorine atoms; ring G, ring I andring J independently represent trans-1,4-cyclohexylene,pyrimidine2,5-diyl, or 1,4-phenylene whose hydrogen atoms may besubstituted by fluorine atoms; Z₇ and Z₈ independently represent —C≡C—,—COO—, —CH₂CH₂—, —CH═CH— or a covalent bond; and any atom constitutingthese compounds may be subsituted by its isotope.

The following compounds can be preferably exemplified as the compoundsof general formula (2)-(4), which are used in the present invention.

wherein R₁ and X₁ have the same meaning as described above.

The compounds represented by general formula (2)-(4) have positivedielectric anisotropy values, excellent thermal and chemical stability,and are especially useful for preparing liquid crystal compositions forTFT which require high reliability, i.e. high voltage holding ratio andhigh specific resistance.

For the preparation of liquid crystal compositions for TFT, thequantities of the compounds represented by general formula (2)-(4) maybe within the range of 0.1 to 99.9% by weight, preferably 10 to 97% byweight, and more preferably 40 to 95% by weight relative to the totalweight of the liquid crystal composition. The compounds represented bygeneral formula (7)-(9) may further be contained for adjustment ofviscosity.

The compounds represented by general formula (2)-(4) may also be usedfor the preparation of liquid crystal compositions for STN and TNdisplays. The quantities of the compounds are preferably 50% by weightor less.

As the compounds represented by general formula (5) or (6), thefollowing compounds are preferably used.

wherein R₂, R₃ and X₂ have the same meaning as shown in the above.

The compounds represented by general formula (5) or (6) have highpositive dielectric anisotropy values, and are used especially forlowering the threshold voltage of the liquid crystal composition. Thecompounds are also used for adjusting optical anisotropy values andexpanding the nematic range through, for example, raising clearingpoints. Further, the compounds are used for improving the sharpness ofliquid crystal compositions for STN and TN.

The compounds represented by general formula (5) or (6) are especiallyuseful for preparing liquid crystal compositions for STN and TN.

When the quantity of the compounds represented by general formula (5) or(6) is increased, the threshold voltage of the liquid crystalcompositions is lowered and the viscosity is increased. Accordingly, solong as the viscosity of the liquid crystal composition satisfiesrequirements, use of such compounds in large quantities is advantageousfor low-voltage operation. The quantity of the compounds represented bygeneral formula (5) or (6), in case of preparation of liquid crystalcompositions for STN or TN, may be within the range of 0.1 to 99.9% byweight, preferably 10-97% by weight, and more preferably 40-95% byweight.

Preferred compounds represented by general formula (7)-(9) may beexemplified below.

wherein R₄ and R₅ have the same meaning as described above.

The compounds represented by general formula (7)-(9) have small absolutevalues of dielectric anisotropy, and these are nearly neutral. Thecompounds represented by general formula (7) are mainly used foradjusting viscosity and optical anisotropy values. The compoundsrepresented by general formula (8) or (9) aremainlyusedfor expanding thenematic range through, for example, raising clearing points or adjustingoptical anisotropy values.

Increase in the quantity of the compounds represented by general formula(7)-(9) increases the threshold voltage and lowers the viscosity of theliquid crystal composition. Therefore, so long as the threshold voltageof the liquid crystal composition satisfies requirements, use of thecompounds in large quantities is preferred. The quantity of thecompounds represented by general formula (7)-(9), in case of preparationof liquid crystal compositions for TFT, may be 40% by weight or less,preferably 35% by weight or less. In case of preparation of liquidcrystal compositions for STN and TN, it may be preferably 70% by weightor less, and more preferably 60% by weight or less.

Moreover, in the present invention, except in special cases such asliquid crystal compositions for an OCB (Optically CompensatedBirefringence) mode, an optically active compound is normally added tothe liquid crystal composition of the present invention for adjustingrequired twist angle by inducing formation of the helical structure ofthe liquid crystal composition, and for preventing reverse twist.Although any known optically active compounds used for the abovepurposes may be used in the present invention, preferred compoundsinclude the following optically active compounds.

In the liquid crystal compositions of the present invention, the pitchof twist is adjusted by addition of these optically active compounds.The pitch of twist is preferably adjusted within the range of 40-200 μmfor liquid crystal compositions for TFT and TN, and 6-20 μm for liquidcrystal compositions for STN. In case of a bistable TN mode, it ispreferably adjusted within the range of 1.5-4 μm. For adjustment of thetemperature dependence of the pitch, two or more optically activecompounds may be added.

The liquid crystal compositions of the present invention are prepared bywell known methods. In general, a method in which various compounds aredissolved in each other at high temperature is used.

Furthermore, the liquid crystal compositions of the present inventionmay be used as those of the guest-host (GH) mode by adding dichroic dyessuch as merocyanine, styryl, azo, azomethyne, azoxy, quinophthalone,anthraquinone and tetrazine types. Moreover, the compositions may beused for NCAP, which is prepared by micro-capsulation of a nematicliquid crystal, or for a polymer dispersion liquid crystal displaydevice (PDLCD) represented by a polymer network liquid crystal displaydevice (PNLCD), which is prepared by making a polymer of tridimensionalnetwork structure in liquid crystal. In addition, the liquid crystalcompositions may be used for an electrically controlled birefringence(ECB) mode or a dynamic scattering (DS) mode.

The following liquid crystal compositions containing the compounds ofthe present invention can be exemplified. Moreover, the compounds in thecomposition examples and undermentioned working examples are representedin accordance with the following rule by brief symbols, and the numbersof the compounds are the same as those in the following examples.Further, in the composition examples and working examples, exceptprevious notice, “%” means “% by weight”.

Rc-Aa-Za˜---˜---˜Zn-Ac-Rd Left end group Rc C_(a)H_(2a+1)— a-C_(a)H_(2a+1)O— aO- C_(a)H_(2a+1)OC_(b)H_(2b)— aOb—C_(a)H_(2a+1)OC_(b)H_(2b)O— aObO—C_(a−1)H_(2(a−1)+1)C(C_(b)H_(2b+1))HC_(c)H_(2c)— a(b)c-CFH₂C_(a−1)H_(2(a−1))— Fa- CF₂HC_(a−1)H_(2(a−1))— FFa-CF₃C_(a−1)H_(2(a−1))— FFFa- CFH₂C_(a−1)H_(2(a−1))O— FaO—CFH₂C_(a−1)H_(2(a−1))OC_(b)H_(2b)— FaOb- C_(a)H_(2a+1)CFHC_(b)H_(2b)—a(f)b- C_(a)H_(2a+1)CF₂C_(b)H_(2b)— a(FF)b-C_(a)H_(2a+1)CH═CHC_(b)H_(2b)— aVb-C_(a)H_(2a+1)CH═CHC_(b)H_(2b)CH═CHC_(c)H_(2c)— aVbVc-C_(a)H_(2a+1)CH═CHC_(b)H_(2b)OC_(c)H_(2c)— aVbOc-C_(a)H_(2a+1)OC_(b)H_(2b)CH═CHC_(c)H_(2c)— aObVc-CFH₂C_(a−1)H_(2(a−1))CH═CHC_(b)H_(2b)— FaVb- FFC═CHC_(a)H_(2a)— FFVa-F(CN)C═CHC_(a)H_(2a)— FCVa- Bonding group Za˜Zn —(CH₂)_(a)— a —CH₂O—CH₂O —OCH₂— OCH₂ —C₃H₆O— C₃H₆O —OC₃H₆— OC₃H₆ —COO— E —C≡C— T —CH═CH— V—CF₂O— CF₂O —OCF₂— OCF₂ Ring structure Aa˜Ao

B

B(F,F)

B(2F)

B(F,Cl)

B(F)

H

B(Cl)

Py

B(2,3F)

D

B(2,3Cl)

Ch Right end group Rd —F —F —Cl —CL —CN —C —CF₃ —CF3 —OCF₃ —OCF3 —OCF₂H—OCF2H —OCF₂CF₂H —OCF2CF2H —OCF₂CFHCF₂ —OCF2CFHCF3 —C_(w)H_(2w+1) -w—OC_(w)H_(2w+1) —Ow —C_(w)H_(2w)CH═CH₂ -wV—C_(w)H_(2w)CH═CHC_(x)H_(2x+1) -wVx —COOCH₃ -EMe—C_(w)H_(2w)CH+CHC_(x)H_(2x)F -wVxF —CH═CF₂ -VFF —C_(w)H_(2w)CH═CF₂-wVFF —C≡C—CN -TC

Furthermore, for example, in the following partial structural formula,when the hydrogen atom of trans-1,4-cyclohexylene is substituted by aheavy hydrogen atom (D) at the positions of Q., Q, and Q₃, it isrepresented by a symbol H[1D, 2D, 3D], and when the hydrogen atom issubstituted by a heavy hydrogen atom at the positions of Q₅, Q₆ and Q₇,it is represented by a symbol H[5D, 6D, 7D].

Composition Example 1 F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 5.0%F5-B(F)2B(F,F)B(F)—CL (Compound No.79) 5.0% 1V2-BEB(F,F)—C 5.0% 3-HB—C20.0% 2-BTB-1 10.0% 3-HH-4 11.0% 3-HHB-1 11.0% 3-HHB-3 9.0% 3-H2BTB-24.0% 3-H2BTB-3 4.0% 3-H2BTB-4 4.0% 3-HB(F)TB-2 6.0% 3-HB(F)TB-3 6.0%CM33 0.8 parts Composition Example 2 F2-BB(F)2B(F,F)—CF₃ (CompoundNo.89) 5.0% FF3-B(F)B(F)B(F)—F (Compound No.15) 3.0% V2-HB—C 12.0%1V2-HB—C 12.0% 3-HB—C 10.0% 3-H[1D,2D,3D]-C 9.0% 3-HB(F)—C 5.0% 2-BTB-12.0% 3-HH-4 8.0% 3-HH—VFF 6.0% 2-H[1D,2D,3D]HB—C 3.0% 3-HHB—C 3.0%3-HB(F)TB-2 8.0% 3-H2BTB-2 5.0% 3-H2BTB-3 5.0% 3-H2BTB-4 4.0%Composition Example 3 F4-B2B(F,F)B(F)—OCF₃ (Compound No.89) 5.0%F3-B(F,F)B(F)BCL (Compound No.9) 4.0% 301-BEB(F)—C 15.0% 401-BEB(F)—C13.0% 501-BEB(F)—C 13.0% 2-HHB(F)—C 15.0% 3-HHB(F)—C 15.0% 3-HB(F)TB-24.0% 3-HB(F)TB-3 4.0% 3-HHB-1 8.0% 3-HHB-01 4.0% Composition Example 4F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 5.0% 2(F)1-BB(F)B(F)—CF₃(Compound No.7) 2.0% 1(FF)3-BB(F)B(F,F)—OCF₃ (Compound No.13) 4.0%5-PyB—F 4.0% 3-PyB(F)—F 4.0% 2-BB—C 5.0% 5-BB—C 5.0% 2-PyB-2 2.0%3-PyB-2 2.0% 6-PyB-05 3.0% 6-PyB-06 3.0% 6-PyB-07 3.0% 3-PyBB—F 6.0%4-PyBB—F 6.0% 5-PyBB—F 6.0% 3-HHB-1 4.0% 3-HHB-3 8.0% 2-H2BTB-2 4.0%2-H2BTB-3 4.0% 2-H2BTB-4 5.0% 3-H2BTB-2 5.0% 3-H2BTB-3 5.0% 3-H2BTB-45.0% Composition Example 5 F5-B(F)2B(F,F)B(F)—CL (Compound No.79) 4.0%F4-B2B(F,F)B(F)—OCF₃ (Compound No.89) 2.0% F2-BB(F)2B(F,F)—CF₃ (CompoundNo.115) 2.0% 3-DB—C 10.0% 4-DB—C 10.0% 2-BEB—C 12.0% 3-PyB(F)—F 6.0%3-HEB-04 8.0% 4-HEB-02 6.0% 5-HEB-01 6.0% 3-HEB-02 5.0% 5-HEB-5 5.0%4-HEB-5 5.0% 10-BEB-2 4.0% 3-HHB-1 6.0% 3-HHEBB—C 3.0% 3-HBEBB—C 3.0%5-HBEBB—C 3.0% Composition Example 6 F5-B(F)B(F,F)B(F)—OCF₃ (CompoundNo.1) 8.0% F5-B(F)2B(F,F)B(F)—CL (Compound No.79) 4.0%FF3-B(F)B(F)B(F)—F (Compound No.15) 4.0% 3-HB—C 10.0% 7-HB—C 3.0%101-HB—C 10.0% 3-HB(F)—C 10.0% 2-PyB-2 2.0% 3-PyB-2 2.0% 4-PyB-2 2.0%101-HH-3 7.0% 2-BTB-01 7.0% 3-HHB-1 7.0% 3-HHB—F 4.0% 3-HHB-01 4.0%3-H2BTB-2 3.0% 3-H2BTB-3 3.0% 2-PyBH-3 4.0% 3-PyBH-3 3.0% 3-PyBB-2 3.0%Composition Example 7 F5-B(F)2B(F,F)B(F)—CL (Compound No.79) 4.0%F3-B(F,F)B(F)B—CL (Compound No.9) 3.0% 201-BEB(F)—C 5.0% 301-BEB(F)—C12.0% 1V2-BEB(F,F)—C 10.0% 3-HH-EMe 10.0% 3-HB-02 18.0% 7-HEB—F 2.0%3-HHEB—F 2.0% 5-HHEB—F 2.0% 3-HBEB—F 4.0% 201-HBEB(F)—C 2.0%3-HB(F)EB(F)—C 2.0% 3-HBEB(F,F)—C 2.0% 3-HHB—F 4.0% 3-HHB-01 4.0%3-HHB-3 10.0% 3-HEBEB—F 2.0% 3-HEBEB-1 2.0% Composition Example 8F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 3.0% F5-B(F)2B(F,F)B(F)—CL(Compound No.79) 3.0% 5-BEB(F)—C 5.0% V—HB—C 11.0% 5-PyB—C 6.0% 4-BB-311.0% 3-HH-2V 10.0% 5-HH—V 11.0% V—HHB-1 7.0% V2-HHB-1 15.0% 3-HHB-13.0% 1V2-HBB-2 10.0% 3-HHEBH-3 5.0% Composition Example 9FF3-B(F)B(F)B(F)—F (Compound No.15) 4.0% F5-B(F)2B(F,F)B(F)—CL (CompoundNo.79) 4.0% F3-B(F,F)B(F)B—CL (Compound No.9) 4.0% 201-BEB(F)—C 5.0%301-BEB(F)—C 12.0% 1V2-BEB(F,F)—C 16.0% 3-HB-02 10.0% 3-HH-4 3.0%3-HHB-F 3.0% 3-HHB-1 4.0% 3-HHB-01 4.0% 3-HBEB—F 4.0% 3-HHEB—F 7.0%5-HHEB—F 7.0% 3-H2BTB-2 4.0% 3-H2BTB-3 4.0% 3-HB(F)TB-2 5.0% CompositionExample 10 F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 8.0%F4-B2B(F,F)B(F)—OCF₃ (Compound No.89) 3.0% F2-BB(F)2B(F,F)—CF₃ (CompoundNo.115) 2.0% 2-BEB—C 12.0% 3-BEB—C 4.0% 4-BEB—C 6.0% 3-HB—C 20.0%3-HEB-04 12.0% 4-HEB-02 8.0% 5-HEB-01 8.0% 3-HEB-02 6.0% 3-HHB-1 7.0%3-HHB-01 4.0% Composition Example 11 F5-B(F)B(F,F)B(F)—OCF₃ (CompoundNo.1) 7.0% F3-B(F,F)B(F)B—CL (Compound No. 9) 3.0% F2-BB(F)2B(F,F)—CF₃(Compound No.115) 3.0% 2-BEB—C 10.0% 5-BB—C 12.0% 7-BB—C 7.0% 2-BTB-110.0% 10-BEB-2 10.0% 10-BEB-5 12.0% 2-HHB-1 4.0% 3-HHB—F 4.0% 3-HHB-17.0% 3-HHB-01 4.0% 3-HHB-3 7.0% Composition Example 12 F3-B(F,F)B(F)B—CL(Compound No.9) 6.0% 2(F)1-BB(F)B(F)—CF₃ (Compound No.7) 6.0%1V2-BEB(F,F)—C 10.0% 3-HB—C 10.0% V2V—HB—C 14.0% V2V—HH-3 19.0% 3-HB-024.0% 3-HHB-1 10.0% 3-HHB-3 5.0% 3-HB(F)TB-2 4.0% 3-HB(F)TB-3 4.0%3-H2BTB-2 4.0% 3-H2BTB-3 4.0% Composition Example 13F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 3.0% F4-B2B(F,F)B(F)—OCF₃(Compound No.89) 3.0% 2(F)1-BB(F)B(F)—CF₃ (Compound No.7) 3.0%1(FF)3-BB(F)B(F,F)—OCF₃ (Compound No.13) 2.0% 5-BTB(F)TB-3 10.0%V2-HB-TC 10.0% 3-HB-TC 10.0% 3-HB—C 10.0% 5-HB—C 7.0% 5-BB—C 3.0%2-BTB-1 10.0% 2-BTB-01 5.0% 3-HH-4 5.0% 3-HHB-1 10.0% 3-H2BTB-2 3.0%3-H2BTB-3 3.0% 3-HB(F)TB-2 3.0% Composition Example 14FF3-B(F)B(F)B(F)—F (Compound No.15) 4.0% 1V2-BEB(F,F)—C 6.0% 3-HB—C18.0% 2-BTB-1 10.0% 5-HH—VFF 30.0% 1-BHH—VFF 8.0% 1-BHH-2VFF 11.0%3-H2BTB-2 5.0% 3-H2BTB-3 4.0% 3-HHB-1 4.0% Composition Example 15F3-B(F,F)B(F)B—CL (Compound No.9) 7.0% FF3-B(F)B(F)B(F)—F (CompoundNo.15) 7.0% 2-HB—C 5.0% 3-HB—C 12.0% 3-HB-02 15.0% 2-BTB-1 3.0% 3-HHB-18.0% 3-HHB—F 4.0% 3-HHB-01 5.0% 3-HHEB—F 4.0% 5-HHEB—F 4.0% 2-HHB(F)—F7.0% 3-HHB(F)—F 7.0% 5-HHB(F)—F 7.0% 3-HHB(F,F)—F 5.0% CompositionExample 16 F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 7.0%F5-B(F)2B(F,F)B(F)—CL (Compound No.79) 6.0% 2-HHB(F)—F 17.0% 3-HHB(F)—F17.0% 5-HHB(F)—F 16.0% 2-H2HB(F)—F 10.0% 3-H2HB(F)—F 5.0% 5-H2HB(F)—F10.0% 2-HBB(F)—F 6.0% 3-HBB(F)—F 6.0% CN 0.3% Composition Example 17FF3-B(F)B(F)B(F)—F (Compound No.15) 5.0% 1(FF)3-BB(F)B(F,F)—OCF₃(Compound No.13) 5.0% F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 3.0%F3-B(F,F)B(F)B—CL (Compound No.9) 3.0% F4-B2B(F,F)B(F)—OCF₃ (CompoundNo.89) 4.0% 3-HB-02 10.0% 3-HH-4 2.0% 3-HH[5D,6D,7D]-4 3.0% 2-HHB(F)—F10.0% 3-HHB(F)—F 10.0% 5-HH[5D,6D,7D]B(F)—F 10.0% 3-H2HB(F)—F 5.0%2-HBB(F)—F 3.0% 3-HBB(F)—F 3.0% 2-H2BB(F)—F 5.0% 3-H2BB(F)—F 6.0%3-HHB-1 8.0% 3-HHB-01 5.0% Composition Example 18 F5-B(F)B(F,F)B(F)—OCF₃(Compound No.1) 4.0% F5-B(F)2B(F,F)B(F)—CL (Compound No.79) 4.0%F4-B2B(F,F)B(F)—OCF₃ (Compound No.89) 4.0% FF3-B(F)B(F)B(F)—F (CompoundNo.15) 4.0% 7-HB(F,F)—F 3.0% 3-HB-02 7.0% 2-HHB(F)—F 10.0% 3-HHB(F)—F10.0% 5-HHB(F)—F 10.0% 2-HBB(F)—F 9.0% 3-HBB(F)—F 9.0% 2-HBB—F 4.0%3-HBB—F 4.0% 5-HBB—F 3.0% 5-HBB(F,F)—F 5.0% 3-HBB(F,F)—F 10.0%Composition Example 19 2(F)1-BB(F)B(F)—CF₃ (Compound No.7) 5.0%1(FF)3-BB(F)B(F,F)—OCF₃ (Compound No.13) 5.0% 7-HB(F,F)—F 3.0%3-H2HB(F,F)—F 12.0% 4-H2HB(F,F)—F 10.0% 3-HHB(F,F)—F 5.0% 4-HBB(F,F)—F5.0% 3-HH2B(F,F)—F 15.0% 5-HH2B(F,F)—F 10.0% 3-HBB(F,F)—F 12.0%5-HBB(F,F)—F 12.0% 3-HBCF2OB(F,F)—F 6.0% Composition Example 20F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 5.0% F2-BB(F)2B(F,F)—CF₃(Compound No.115) 3.0% F3-B(F,F)B(F)B—CL (Compound No.9) 3.0%7-HB(F,F)—F 5.0% 3-H2HB(F,F)—F 12.0% 4-H2HB(F,F)—F 10.0% 3-HHB(F,F)—F10.0% 3-HBB(F,F)—F 10.0% 3-HHEB(F,F)—F 10.0% 2-HBEB(F,F)—F 3.0%3-HBEB(F,F)—F 5.0% 5-HBEB(F,F)—F 3.0% 3-HDB(F,F)—F 15.0% 3-HHBB(F,F)—F6.0% Composition Example 21 F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 7.0%F4-B2B(F,F)B(F)—OCF₃ (Compound No.89) 7.0% 3-HB—CL 10.0% 5-HB—CL 5.0%7-HB—CL 5.0% 101-HH-5 6.0% 2-HBB(F)—F 8.0% 3-HBB(F)—F 8.0% 4-HHB—CL 8.0%5-HHB—CL 8.0% 3-H2HB(F)—CL 5.0% 3-HBB(F,F)—F 10.0% 5-H2BB(F,F)—F 9.0%3-HB(F)VB-2 4.0% Composition Example 22 F5-B(F)2B(F,F)B(F)—CL (CompoundNo.79) 4.0% 2(F)1-BB(F)B(F)—CF₃ (Compound No.7) 4.0% 3-HHB(F,F)—F 9.0%3-H2HB(F,F)—F 8.0% 4-H2HB(F,F)—F 8.0% 3-HBB(F,F)—F 21.0% 5-HBB(F,F)—F20.0% 3-H2BB(F,F)—F 10.0% 5-HHBB(F,F)—F 3.0% 5-HHEBB—F 2.0%3-HH2BB(F,F)—F 3.0% 101-HBBH-4 4.0% 101-HBBH-5 4.0% Composition Example23 F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 3.0% F3-B(F,F)B(F)B—CL(Compound No.9) 3.0% 2(F)1-BB(F)B(F)—CF₃ (Compound No.7) 2.0%1(FF)3-BB(F)B(F,F)—OCF₃ (Compound No.13) 2.0% 5-HB—F 12.0% 6-HB—F 9.0%7-HB—F 7.0% 2-HHB—OCF₃ 7.0% 3-HHB—OCF₃ 7.0% 4-HHB—OCF₃ 7.0% 5-HHB—OCF₃5.0% 3-HH2B—OCF₃ 4.0% 5-HH2B—OCF₃ 4.0% 3-HHB(F,F)—OCF₃ 5.0% 3-HBB(F)—F10.0% 3-HH2B(F)—F 3.0% 3-HB(F)BH-3 3.0% 5-HBBH-3 3.0% 3-HHB(F,F)—OCF₂H4.0% Composition Example 24 F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 2.0%FF3-B(F)B(F)B(F)—F (Compound No.15) 2.0% 5-H4HB(F,F)—F 7.0% 5-H4HB—OCF₃15.0% 3-H4HB(F,F)—CF₃ 8.0% 5-H4HB(F,F)—CF₃ 10.0% 3-HB—CL 6.0%2-H2BB(F)—F 5.0% 3-H2BB(F)—F 10.0% 5-HVHB(F,F)—F 5.0% 3-HHB—OCF₃ 5.0%3-H2HB—OCF₃ 5.0% V—HHB(F)—F 5.0% 3-HHB(F)—F 5.0% 5-HHEB—OCF₃ 2.0%3-HBEB(F,F)—F 5.0% 5-HH—V2F 3.0% Composition Example 25F5-B(F)B(F,F)B(F)—OCF₃ (Compound No.1) 3.0% F4-B2B(F,F)B(F)—OCF₃(Compound No.89) 3.0% F2-BB(F)2B(F,F)—CF₃ (Compound No.115) 2.0%2(F)1-BB(F)B(F)—CF₃ (Compound No.7) 2.0% 2-HHB(F)—F 2.0% 3-HHB(F)—F 2.0%5-HHB(F)—F 2.0% 2-HBB(F)—F 6.0% 3-HBB(F)—F 6.0% 2-H2BB(F)—F 9.0%3-H2BB(F)—F 9.0% 3-HBB(F,F)—F 25.0% 5-HBB(F,F)—F 19.0% 101-HBBH-4 5.0%101-HBBH-5 5.0% Composition Example 26 F3-B(F,F)B(F)B—CL (Compound No.9)7.0% FF3-B(F)B(F)B(F)—F (Compound No.15) 6.0% 5-HB—CL 12.0% 3-HH-4 7.0%3-HB-02 15.0% 3-H2HB(F,F)—F 8.0% 3-HHB(F,F)—F 3.0% 3-HBB(F,F)—F 6.0%2-HHB(F)—F 5.0% 3-HHB(F)—F 5.0% 5-HHB(F)—F 5.0% 2-H2HB(F)—F 2.0%3-HHBB(F,F)—F 4.0% 3-HBCF₂OB—OCF₃ 4.0% 5-HBCF₂OB(F,F)—CF₃ 4.0% 3-HHB-13.0%

BEST MODE FOR CARRYING OUT THE INVENTION

The following examples illustrate the present invention morespecifically. In each example, C means a crystal, SA means a smectic Aphase, SB means a smetic B phase, SX means a smetic phase notdetermined, N means a nematic phase, Iso means an isotropic phase, andthe unit of phase transition temperature is ° C.

EXAMPLE 1

Preparation of 4″-(5-fluoropentyl)-2,3,5-trifluoro-4-iodobiphenyl(Compound represented by general formula (1) wherein m is 0; R is5-fluoropentyl; X is OCF₃; Y₂, Y₆, Y₈ and Y₁₀ are F; Y₁, Y₃, Y₄, Y₅, Y₇,Y₉, Y₁₁ and Y₁₂ are H; and Z₁ and Z₂ are covalent bonds (Compound No.1))

(Step 1) Preparation of 3-(5-fluoropentyl)fluorobenzene

To a mixture of 4-fluorobutyltriphenylphosphonium bromide 273 g (660mmol) and tetrahydrofuran (abbreviated THF hereinafter) 1000 ml,potasium-tert-butoxide 88 g (684 mmol) was added under ice cooling andstirred for one hour. Then, under ice cooling, a solution of3-fluorobenzaldehyde 74 g (596 mmol) in THF 200 ml was added dropwise,and the mixture was stirred for one hour at room temperature. Thereaction mixture was poured into hexane 1000 ml, and the crystalsdeposited were filtered off. The filtrate was concentrated, anddistilled (93° C./6 mmHg) to obtain 3-(5-fluoro-1-pentenyl)fluorobenzene86 g. (Yield:79.6%).

Then, 5% Pd—C 4 g and ethanol 100 ml were added to3-(5-fluoro-1-pentenyl) fluorobenzene 86 g (472 mmol) to conduct areaction of catalytic hydrogenation reduction. After the hydrogenabsorption was stopped, the catalyst was filtered off, and the filtratewas distilled(62° C./2 mmHg) to obtain 3-(5-fluoropentyl) fluorobenzene56 g. (Yield: 64.4%).

(Step 2) Preparation of 2-fluoro-4-(5-fluoropentyl)iodobenzene

To a solution of 3-(5-fluoropentyl) fluorobenzene 10.0 g (54.3 mmol),which was obtained at the above step, in THF 50 ml, sec-BuLi (1.05 M,cyclohexane solution) 57 ml (corresponding to 59.7 mmol) was addeddropwise so as to maintain −60° C. or less. After the addition, themixture was stirred for 2 hours. Then, a solution of iodide 15.2 g (59.7mmol) in THF 60 ml was added dropwise to maintain −60° C. or less, andthe mixture was stirred for one hour at the same temperature.

After a solution of 1 N HCl 100 ml was added dropwise to the reactionsolution, the mixture was extracted with heptane 150 ml. The resultingorganic layer was washed three times with a diluted water solution ofNaHCO₃ and three times with water, and dried over anhydrous magnesiumsulfate. The solvent was distilled off under reduced pressure, and theresidue was purified by silica-gel column chromatography (eluent:hexane) to obtain crude 2-fluoro-4-(5-fluoropentyl) iodobenzene 13.7 g.(Yield: 81.8%)

(Step 3) Preparation of 4′-(5-fluoropentyl)-2′1,3,5-trifluorobiphenyl

A mixture of 2-fluoro-4-(5-fluoropentyl) iodobenzene 13.7 g (44.2 mmol)obtained at the above step, dihydroxy(3,5-difluorophenyl) borane 8.3 g(53.0 mmol), K₂CO₃ 12.2 g (88.3 mmol), 5% Pd—C 1.3 g and mixed solventof toluene/ethanol/water (1/1/1) 30 ml was heated and refluxed for 8hours. After the catalyst was filtered off, the mixture was extractedwith toluene 200 ml, the resulting organic layer was washed with waterthree times and dried over anhydrous magnesium sulfate. The solvent wasdistilled off under reduced pressure, and the residue was purified bysilica-gel column chromatography (eluent: heptane) to obtain crude4′-(5-fluoropentyl)-2′,3,5-trifluorobiphenyl 10.5 g.

(Yield: 80.6%).

(Step 4) Preparation of2′-fluoro-4′-(5-fluoropentyl)-3,5-difluoro-4-iodobiphenyl

To a solution of 2′-fluoro-4′-(5-fluoropentyl)-3,5-difluorobiphenyl 5.0g (16.9 mmol) obtained at the above step in THF 25 ml, n-BuLi (1.6 M,THF solution) 16 ml (corresponding to 25.3 mmol) was added dropwise tomaintain at −60° C. or less, and the mixture was stirred at the sametemperature for one hour. Then, a solution of iodine 6.6 g (26.2 mmol)in THF 35 ml added dropwise to maintain at −60° C. or less, and themixture was stirred for one hour at the same temperature.

To the reactant, 1N-HCl 50 ml was added dropwise, and the mixture wasextracted with heptane 100 ml. The resulting organic layer was washedthree times with a diluted water solution of NaHCO₃ and three times withwater, and dried over anhydrous magnesium sulfate. The solvent wasdistilled off under reduced pressure, and the residue was purified bysilica-gel column chromatography (eluent: heptane) to obtain crude2′-fluoro-4′-(5-fluoropentyl)-3,5-difluoro-4-iodobiphenyl 6.1 g. (Yield:86.2 %)

(Step 5) Preparation of4″-(5-fluoropentyl)-2,3,5-trifluoro-4-iodobiphenyl

A mixture of 2′-fluoro-4′-(5-fluoropentyl)-3,5-difluoro-4-iodobiphenyl3.0 g (7.1 mmol) obtained at the above step,dihydroxy(3-fluoro-4-trifluoromethoxy phenyl) borane 1.9 g (9.2 mmol),K₂CO₃ 2.0 g (14.2 mmol), 5% Pd—C 0.3 g and mixed solvent oftoluene/ethanol/water (1/1/1) 30 ml was heated and refluxed for 12hours. After the catalyst was filtered off, the mixture was extractedwith toluene 100 ml, the resulting organic layer was washed with waterthree times and dried over anhydrous magnesium sulfate. The solvent wasdistilled off under reduced pressure, and the residue was purified bysilica-gel column chromatography (eluent: heptane) to obtain crude4″-(5-fluoropentyl)-2,3,5-trifluoro-4-iodobiphenyl 3.2 g. The compoundwas recrystallized from mixed solvent of heptane/ethyl acetate (9/1) toobtain the title compound 1.9 g. (Yield: 56.4%)

The phase transition temperature of the product was C 87.2-88.2 Iso.

The structure was supported well by the spectral data.

Mass spectrum analysis: 474 (M⁺); ¹H-NMR (CDCl₃, TMS internal standard);δ(ppm); 1.32-2.09 (m, 6H); 2.69 (t, 2H); 4.11-4.82 (d, t, 2H); 6.95-7.34(m, 8H).

By using the same method as in Example 1, the following compounds can beproduced. In the following example, the compounds are represented byabbreviations according to the above rules.

Compound No.2: F2-B(F,F)BB-F

Compound No.3: F3-B(F)B(F)-CF₃

Compound No.4: F4-B(F)BB(F)-OCF₃

Compound No.5: F5-BB(F,F)B-CF₂H

Compound No.6: F6-BB(F)B(F)-OCF₂H

Compound No.7: 2(F)1-BB(F)B(F)-CF₃

Compound No.8: F7-BBB(F,F)-CF₃

Compound No.9: F3-B(F,F)B(F)B-CL

Compound No.10: F9-B(F,F)BB(F)-CL

Compound No.11: F10-B(F)B(F,F)B-CFH₂

Compound No.12: F15-BB(F,F)B(F)-OCF₃

Compound No.13: 1(FF)3-BB(F)B(F,F)-OCF₃

Compound No.14: F20-B(F)B(F)B(F)-CF₃

Compound No.15: FF3-B(F)B(F)B(F)-F

Compound No.16: F3-B(F,F)B(F,F)B-OCF₂H

Compound No.17: F3-B(F,F)B(F)B(F)-CF₂H

Compound No.18: FFF3-B(F,F)B(F)B(F)-OCF₃

Compound No.19: F50-B(F)B(F,F)B(F)-CL

Compound No.20: F5-B(F)B(F)B(F,F)-OCF₃

Compound No.21: F2-B(F,F)B(F,F)B(F)-CF₂H

Compound No.22: F2-B(F,F)B(F)B(F,F)-OCF₂H

Compound No.23: F4-B(F)B(F,F)B(F,F)-CL

Compound No.24: F4-B(F,F)B(F,F)B(F,F)-F

Compound No.25: F3-B(F,F)BBB-F

Compound No.26: F3-B(F)B(F)BB-CL

Compound No.27: F3-B(F)BB(F)B-C F₃

Compound No.28: F5-B(F)BBB(F)-CF₂H

Compound No.29: F5-B(F,F)B(F)BB-CFH₂

Compound No.30: F5-B(F,F)BB(F)B-OCF₃

Compound No.31: F2-B(F,F)BBB(F)-OCF₂H

Compound No.32: F2-B(F)B(F,F)BB-CF₂H

Compound No.33: F2-BB(F,F)B(F)B-OCF₂H

Compound No.34: F4-BB(F,F)BB(F)-F

Compound No.35: F4-B(F)BB(F,F)B-CL

Compound No.36: F4-BB(F)B(F,F)-OCF₃

Compound No.37: F1-BBB(F,F)B(F)-OCF₃

Compound No.38: F1-B(F)B(F)B(F)B-CFH₂

Compound No.39: F13-B(F,F)B(F,F)BB-CF₃

Compound No.40: F7-B(F,F)B(F)B(F)B-CF₂H

Compound No.41: F7-B(F,F)B(F)BB(F)-F

Compound No.42: F7-B(F,F)BB(F)B(F)-CL

Compound No.43: F6-B(F,F)BB(F,F)B-OCF₃

Compound No.44: F6-B(F,F)BBB(F,F)-CL

Compound No.45: F6-B(F)B(F,F)B(F)B-CF₂H

Compound No.46: F9-B(F)B(F,F)BB(F)-CFH₂

Compound No.47: F2-BB(F,F)B(F)B(F)-CF₃

Compound No.48: F2-BB(F,F)B(F,F)B-OCF₂H

Compound No.49: F2B-B(F,F)BB(F,F)-F

Compound No.50: F3-B(F)B(F)B(F,F)B-F

Compound No.51: F3-B(F)BB(F,F)B(F)-OCF₃

Compound No.52: F3-BBB(F,F)B(F,F)-CF₃

Compound No.53: F3-B(F)B(F)B(F.F)-OCF₂H

Compound No.54: F3-B(F)BB(F)B(F,F)-CF₂H

Compound No.55: F3-BB(F)B(F)B(F,F)-CFH₂

Compound No.56: F4-B(F,F)B(F,F)B(F)B-CL

Compound No.57: F4-B(F,F)B(F,F)BB(F)-F

Compound No.58: F4-B(F,F)B(F)B(F)B(F)-F

Compound No.59: F4-B(F,F)B(F)B(F,F)B-CF₂

Compound No.60: F4-B(F,F)BB(F,F)B(F)-OCF₂H

Compound No.61: F5-B(F,F)B(F)BB(F,F)-CF₂H

Compound No.62: F5-B(F,F)BB(F)B(F,F)-CFH₂

Compound No.63: F5-B(F)B(F,F)B(F,F)B-OCF₃

Compound No.64: FS-BB(F,F)B(F,F)B(F)-CF₃

Compound No.65: F5-B(F)B(F,F)B(F)B(F)-CL

Compound No.66: F6-B(F)B(F,F)BB(F,F)-CF₃

Compound No.67: F6-BB(F,F)B(F)B(F,F)-OCF₃

Compound No.68: F6-B(F)B(F)B(F,F)B(F)-F

Compound No.69: F6-B(F)BB(F,F)B(F,F)-CL

Compound No.70: F6-BB(F)B(F,F)B(F,F)-OCF₂H

Compound No.71: F7-B(F)B(F)B(F)B(F,F)-CF₂H

Compound No.72: F7-B(F,F)B(F,F)B(F,F)B-CF₂H

Compound No.73: F7-B(F,F)B(F,F)B(F)B(F)-F

Compound No.74: F7-B(F,F)B(F,F)BB(F,F)-CL

Compound No.75: F7-B(F,F)B(F)B(F,F)B(F)-CF₃

Compound No.76: F7-B(F,F)BB(F,F)B(F,F)-OCF₃

Compound No.77: F705-B(F,F)B(F)B(F)B(F,F)-OCF₂H

Compound No.78: F3-B(F,F)B(F,F)B(F,F)B(F,F)-OCF₂CFHCF₃

EXAMPLE 2

Preparation of 4′-(2-(2-fluoro-4-(5-fluoropentyl) phenyl)ethyl)-2′,6′,3-trifluoro-4-chlorobiphenyl (Compound represented bygeneral formula (1) wherein m is 0; R is 5-fluoropentyl; X is Cl; Y₂,Y₆, Y₈ and Y₁₀ are F; Y₁, Y₃, Y₄, Y₅, Y₇, Y₉, Y₁₁, and Y₁₂ are H; Z₁ is—(CH₂)₂— and Z₂ is a covalent bond (Compound No.79))

(Step 1) Preparation of1-(2-hydroxy-2-(2-fluoro-4-(5-fluoro-pentyl)phenyl)ethyl)-3,5-difluorobenzene

To a solution of 3-(5-fluoropentyl)fluorobenzene 10.7 g (58.5 mmol)obtained at Step 1 in Example 1 in THF 100 ml, sec-BuLi (1.05 M,cyclohexane solution) 61 ml (corresponding to 64.3 mmol) was addeddropwise to maintain at −60° C. or less, and the mixture was stirred atthe same temperature for 2 hours. A solution of(3,5-difluorophenyl)acetaldehyde 10.5 g (67.3 mmol) in THF 60 ml wasthen added dropwise to maintain at −60° C. or less, and the mixture wasstirred at the same temperature for 5 hours.

After adding dropwise 1N-HCl 100 ml to the reaction solution, themixture was extracted with ethyl acetate 150 ml. The resulting organiclayer was washed three times with a diluted water solution of NaHCO₃ andthen three times with water, and dried over anhydrous magnesium sulfate.The solvent was distilled off under reduced pressure, and the residuewas purified by silica gel column chromatography (eluent: heptane/ethylacetate=8/2) to obtain crude1-(2-hydroxy-2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-3,5-difluorobenzene 9.9 g. (Yield: 49.5%) (Step 2) Preparation of methyl(1-(2-fluoro-4-(5-fluoropentyl)phenyl)-2-(3,5-difluorophenyl))-O-ethyldithiocarbonate

To a mixture of NaOH 30.0 g (749.2 mmol), water 30 ml andtetrabutylammonium hydrogen sulfate 5.1 g (15 mmol), a solution of1-(2-hydroxy-2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-3,5-difluorobenzene 5.1 g (15.0 mmol) obtained at the above step in toluene 30 mlwas added at room temperature, and the mixture was stirred for one hour.Carbon disulfide 2.7 ml (45 mmol) was added, and the mixture was stirredat room temperature for 30 minutes. Methyl iodide 2.8 ml (45 mmol) wasadded, and then the mixture was stirred at room temperature for 2 hours.The reaction solution was poured into water 100 ml, and extracted withtoluene 100 ml. The resulting organic layer was washed three times withwater and dried over anhydrous magnesium sulfate. The solvent wasdistilled off under reduced pressure, and the residue was purified bysilica gel column chromatography (eluent: heptane/toluene=1/1) to obtaincrude methyl (1-(2-fluoro-4-(5-fluoropentyl)phenyl)-2-(3,5-difluorophenyl))-O-ethyldithiocarbonate 3.0 g.

(Yield: 49.2%)

(Step 3) Preparation of 1-(2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-3,5-difluorobenzene

A mixture of methyl(1-(2-fluoro-4-(5-fluoropentyl)phenyl)-2-(3,5-difluorophenyl))-O-ethyldithiocarbonte3.0 g (7.3 mmol) obtained at the above step, 2,2′-azobisisobutylonitrile0.2 g (1.4 mmol) and dried toluene 15 ml was heated at 80° C. ,tri-n-butyl tin hydride 3.9 ml (14.5 mmol) was added dropwise, and themixture was stirred at the same temperature for one hour. The reactionsolution was poured into diluted hydrochloric acid 30 ml and extractedwith toluene 50 ml. The resulting organic layer was washed three timeswith a diluted water solution of NaHCO₃ and then three times with water,and dried over anhydrous magnesium sulfate. The solvent was distilledoff under reduced pressure, and the residue was purified by silica gelcolumn chromatography (eluent: heptane/toluene=9/1) to obtain crude1-(2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-3,5-difluorobenzene 2.1g. (Yield: 91.1%)

(Step 4) Preparation of 1-(2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-3,5-difluoro-4-iodobenzene

To a solution of 1-(2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-3,5-difluorobenzene obtained at the above step 2.1 g (6.6 mmol)in THF 20 ml, n-BuLi 6.2 ml (9.9 mmol) was added dropwise to maintain at−60° C. or less, and then the mixture was stirred at the sametemperature for 2 hours. A solution of iodine 2.7 g (10.6 mmol) in THF10 ml was added dropwise to maintain at −60° C. or less, and the mixturewas stirred for 2 hours at the same temperature.

After 1 N-HCl 30 ml was added dropwise to the reaction solution, themixture was extracted with heptane 50 ml. The resulting organic layerwas washed three times with a diluted water solution of NaHCO₃ and thenthree times with water, and dried over anhydrous magnesium sulfate. Thesolvent was distilled off under reduced pressure, and the residue waspurified by silica gel column chromatography (eluent:heptane/toluene=1/1) to obtain crude1-(2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-3,5-difluoro-4-iodobenzene2.8 g. (Yield: 98.6 %)

(Step 5) Preparation of 4′-(2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-2′,6′,3-trifluoro-4-chlorobiphenyl

A mixture of1-(2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)3,5-difluoro-4-iodobenzeneobtained at the above step 2.5 g (5.8 mmol),dihydroxy(3-fluoro-4-chlorophenyl) borane 1.3 g (7.5 mmol), K₂CO₃ 1.6 g(11.6 nol), 5% Pd—C 0.3 g and mixed solvent of toluene/ethanol/water(1/1/1) 30 ml was refluxed for 13 hours. After the catalyst was filteredoff, the mixture was extracted with toluene 100 ml, the resultingorganic layer was washed with water three times and dried over anhydrousmagnesium sulfate. The solvent was distilled off under reduced pressure,and the resulting residue was purified by silica-gel columnchromatography (eluent: heptane/toluene=9/1) to obtain crude4′-(2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-2′,6′,3-trifluoro-4-chlorobiphenyl 1.6 g. The compound wasrecrystallized from mixed solvent of ethanol/ethyl acetate (85/15) toobtain the title compound 1.3 g. (Yield: 47.7%)

The phase transition temperature of the product was C 53.2-53.6 Iso.

The structure was supported well by the spectral data.

Mass spectrum analysis: 452 (M⁺); ¹H-NMR (CDCl₃, TMS internal standard);δ(ppm); 1.34-2.03 (m, 6H); 2.61 (t, 2H); 2.92 (s, 4H); 4.11-4.77 (d, t,2H); 6.95-7.34 (m, 8H).

By using the same method as in Example 2, the following compounds can beproduced.

Compound No.80: F3-B(F,F)2BB-F

Compound No.81: F301-B(F)2B(F)B-CL

Compound No.82: F3-B(F)2BB(F)-CF₃

Compound No.83: F3-B2B(F,F)B-CF₂H

Compound No.84: F3-B2B(F)B(F)-CFH₂

Compound No.85: F3-B2BB(F,F)-OCF₃

Compound No.86: F4-B(F,F)2B(F)B-OCF₂H

Compound No.87: F4-B(F,F)2BB(F)-F

Compound No.88: F4-B(F)2B(F,F)2B-CL

Compound No.89: F4-B2B(F,F)B(F)-OCF₃

Compound No.90: F5-B(F)2B(F)B(F)-OCF₂H

Compound No.91: F5-B(F)2BB(F,F)-CL

Compound No.92: F5-B2B(F)B(F,F)-CF₃

Compound No.93: F5-B(F,F)2B(F,F)B-OCF₃

Compound No.94: F5-B(F=F)2BB(F,F)-OCF₂H

Compound No.95: F5-B2B(F,F)B(F,F)-OCF₂H

Compound No.96: F2-B(F,F)2B(F)B(F)-CL

Compound No.97: F2-B(F)2B(F,F)B(F)-CFH₂

Compound No.98: F2-B(F)2B(F)B(F,F)-F

Compound No.99: F2-B(F,F)2B(F,F)B(F)-CL

Compound No.100: F2-B(F,F)2B(F)B(F,F)-OCF₃

Compound No.101: F2-B(F)2B(F,F)B(F,F)-CFH₂

Compound No.102: F2-B(F,F)2B(F,F)B(F,F)-OCF₂CFHCF₃

Compound No.103: F1-B(F,F)B2B-F

Compound No.104: F1-B(F)B(F)2B-CL

Compound No.105: F1-B(F)B2B(F)-CF₃

Compound No.106: F1-BB(F,F)2B-CF₂H

Compound No.107: F1-BB(F)2B(F)-CFH₂

Compound No.108: F1-BB2B(F,F)-OCF₃

Compound No.109: F3-B(F,F)B(F)2B-OCF₂H

Compound No.110: F3-B(F,F)B2B(F)-F

Compound No.111: F3-B(F)B(F,F)2B-CL

Compound No.112: F3-BB(F,F)2B(F)-OCF₃

Compound No.113: F6-B(F)B(F)2B(F)-OCF₂H

Compound No.114: F6-B(F)B2B(F,F)-CL

Compound No.115: F2-BB(F)2B(F,F)-CF₃

Compound No.116: F6-B(F,F)B(F,F)2B-OCF₃

Compound No.117: F6-B(F,F)B2B(F,F)-CF₂H

Compound No.118: F6-BB(F,F)2B(F,F)-OCF₂H

Compound No.119: F7-B(F,F)B(F)2B(F)-CL

Compound No.120: F7-B(F)B(F,F)2B(F)-CF₂H

Compound No.121: F7-B(F)B(F)2B(F,F)-F

Compound No.122: F7-B(F,F)B(F,F)2B(F)-CL

Compound No.123: F7-B(F,F)B(F)2B(F,F)-OCF₃

Compound No.124: F7-B(F)B.(FF)2B(F,F)-CF₂H

Compound No.125: F7-B(F,F)B(F,F)2B(F,F)-OCF₂H

Compound No.126: FF2-B(F)B(F,F)2B(F)-CF₃

Compound No.127: 2(F)-B(F)B(F)2B-OCF₃

Compound No.128: F1-B(F,F)2BBB-F

Compound No.129: F2-B(F)B(F)2BB-CL

Compound No.130: F3-B(F)BB(F)2B-CF₃

Compound No.131: F4-B(F)2BBB(F)-CF₂H

Compound No.132: F5-B(F,F)B(F)2BB-CFH₂

Compound No.133: F6-B(F,F)BB(F)2B-OCF₃

Compound No.134: F7-B(F,F)BB2B(F)-OCF₂H

Compound No.135: F8-B(F)2B(F,F)BB-CF₂H

Compound No.136: F9-BB(F,F)2BB-OCF₂H

Compound No.137: F10-BB(F,F)B2B(F)-F

Compound No.138: F15-B(F)2BB(F,F)B-CL

Compound No.139: F2O-BB(F)2B(F,F)B-OCF₃

Compound No.140: F2-BBB(F,F)2B(F)-OCF₃

Compound No.141: F3-B(F)2B(F)B(F)B-CF₂H

Compound No.142: F4-B(F,F)B(F,F)2BB-CF₃

Compound No.143: F5-B(F,F)B(F)B(F)2B-CF₂H

Compound No.144: F6-B(F,F)2B(F)BB(F)-F

Compound No.145: F7-B(F,F)B2B(F)B(F)-CL

Compound No.146: F1-B(F,F)BB(F,F)2B-OCF₃

Compound No.147: F2-B(F,F)2BBB(F,F)-CL

Compound No.148: F3-B(F)B(F,F)2B(F)B-CF₂H

Compound No.149: F4-B(F)B(F,F)B2B(F)-CFH₂

Compound No.150: F5-B2B(F,F)B(F)B(F)-CF₃

Compound No.151: F6-BB(F,F)2B(F.F)B-OCF₂H

Compound No.152: F7-BB(F,F)B2B(F,F)-F

Compound No.153: F6-B(F)2B(F)B(F,F)B-OCF₂H

Compound No.154: F5-B(F)B2B(FF)B(F)-OCF₃

Compound No.155: F4-BBB(F,F)2B(F,F)-CF₃

Compound No.156: F3-B(F)2B(F)BB(F,F) -OCF₂H

Compound No.157: F2-B(F)B2B(F)B(F,F)-CF₂H

Compound No.158: F1-BB(F)B(F)2B(F,F)-CFH₂

Compound No.159: F3-B(F,F)2B(F,F)B(F)B-CL

Compound No.160: F3-B(F,F)B(F,F)2BB(F)-F

Compound No.161: F3-B(F,F)B(F)B(F)2B(F)-OCF₃

Compound No.162: F3-B(F,F)2B(F)B(F,F)B-CF₃

Compound No.163: F3-B(F,F)B2B(F,F)B(F)-OCF₂H

Compound No.164: F4-B(F,F)B(F)B2B(F,F)-CF₂H

Compound No.165: F4-B(F,F)2BB(F)B(F,F)-CFH₂

Compound No.166: F4-B(F)B(F,F)2B(F,F)B-OCF₃

Compound No.167: F4-BB(F,F)B(F,F)2B(F)-CF₃

Compound No.168: F4-B(F,F)2B(F ,F)B (F)B (F)-CL

Compound No.169: F₄-B(F)B(F,F)2B(F,F)—CF₃

Compound No.170: F5-BB(F,F)B(F)2B(F,F)-OCF₃

Compound No.171: F5-B(F)2B(F)B(F,F)B(F)-F

Compound No.172: F5-B(F)B2B(F,F)B(F,F)-CL

Compound No.173: F5-BB(F)B(F,F)2B(F,F)-OCF₂H

Compound No.174: F5-B(F)2B(F)B(F)B(F,F)-CF₂H

Compound No.175: F3-B(F,F)B(F,F)B(F)2B(F)-F

Compound No.176: F3-B(F,F)2B(F,F)BB(F,F)-CL

Compound No.177: F30-B(F,F)B(F)2B(F,F)B(F)-CF₃

Compound No.178: F3-B(F,F)BB(F,F)2B(F,F)-OCF₃

Compound No.179: F3-B(F,F)2B(F)B(F)B(F,F)-OCF₂H

Compound No.180: F5-B(F,F)B(F,F)2B(F,F)B(F,F)-CF₂H

Compound No.181: F5-B4B(F,F)B(F)-CF₃

Compound No.182: F4-B2B(F,F)2B(F,F)-F

Compound No.183: FF2-B(F)B(F,F)2B(F)-CF₃

Compound No.184: F-B(F)B(F)4B-CL

Compound No.185: FFF3-B(F)4B(F)B(F,F)B(F)-F

Compound No.186: F3-BB(F)4B(F)B-OCF₃

Compound No.187: F3-BB(F)B(F)4B-CF₃

EXAMPLE 3

Preparation of(2-fluoro-4-(5-fluoropentyl)phenyl)methyl-2-,3′,4′-trifluorobiphenyl-4-ylether (a compound having general formula (1) in which m is 0; R is5-fluoropentyl; X is F; Y₂, Y₆ and Y₁₀ are F; Y₁, Y₃, Y₄, Y₅, Y₇, Y₈,Y₉, Y₁₁ and Y₁₂ are H; Z₁ is —CH₂O— and Z₂ is a covalent bond (CompoundNo.188))

To a mixture of NaH (60%) 0.6 g (160 mmol) and dimethylformamide(abbreviated as DMF hereinafter) 5 ml,2-fluoro-4-hydroxy-3′,4′-difluorobiphenyl (prepared by a couplingreaction of 3-fluoro-4-iodoanisol anddihydroxy(3,4-difluorophenyl)borane and an elimination reaction of aprotective group) 3.0 g (134 mmol) in DMF 30 ml was added dropwise atroom temperature, and stirred for one hour. A solution of2-fluoro-4-(5-fluoropentyl)iodomethylbenzene (prepared by reduction andiodination of 2-fluoro-4-(5-fluoropentyl)benzaldehyde) 6.1 g (187 mmol)in DMF 30 ml was then added dropwise at room temperature, and stirredfor 3 hours. The mixture was poured into dilute hydrochloric acid 150ml, and extracted with toluene 100 ml. The resulting organic layer waswashed with a diluted water solution of NaHCO₃ and then with water, anddried over anhydrous magnesium sulfate. The solvent was distilled offunder reduced pressure, and the residue was purified by silica gelcolumn chromatography (eluent: heptane/toluene=1/1) to obtain crude(2-fluoro-4-(5-fluoropentyl)phenyl) methyl(2-fluoro-4-(5-fluoropentyl)phenyl)methyl-2-3′,4′-trifluorobiphenyl-4-ylether. The compound was recrystallized from mixed solvent ofethanol/ethyl acetate to obtain the title compound.

According to the same mathod of Example 3, the following compounds canbe prepared.

Compound No.189: F5-B(F,F)OCH₂B(F)B(F,F)-OCF₃

Compound No.190: F4-B(F)C₃H₆OB(F)B(F)-CL

Compound No.191: F3-B(F)O C₃H₆BB(F,F)-CF₃

Compound No.192: F2-B(F,F)B(F)CH₂OB(F)-F

Compound No.193: F3-BB(F)OCH₂B(F,F)-OCF₂H

Compound No.194: F3-BB(F,F)C₃H₆OB(F)-OCF₃

Compound No.195: F30-B(F)BO C₃H₆B(F,F)-CF₃

Compound No.196: F3-BCH₂OB(F)BB(F,F)-CL

Compound No.197: F2-BB(F) CH₂OB(F)B(F)-OCF₃

Compound No.198: F2-B(F)BBCH₂OB(F,F)-OCF₂H

Compound No.199: F2-BC₃H₆OB(F)B(F,F)B-CF₃

Compound No.200: F4-BB(F)C₃H₆OBB(F,F)B(F)-CL

Compound No.201: F5-B(F,F)B(F)BC₃H₆OB(F,F)-OCF₃

Compound No.202: F5-BB(F,F)OC₃H₆BB(F)-CF₂H

Examples using the compounds of the present invention as ingredients ofthe liquid crystal compositions are described as follows. In each usingexample, NI is nematic phase-isotropic phase transition temperature (°C.), Δε is the value of dielectric anisotropy, Δn is the value ofoptical anisotropy, η is viscosity (mPa·s), Vth is threshold voltage(V), and VHR is voltage holding ratio (%).

η was measured at 20° C., Δε, Δn, Vth and pitch of twist P(μm) were eachmeasured at 25° C., and the values of VHR in order from the left weremeasured at 25° C., 80° C. and 100° C., respectively.

EXAMPLE 4

(Using Example 1)

Liquid crystal composition (A) comprising the following cyanophenylcyclohexane type liquid crystal compounds:

3-HB-C 24% 5-HB-C 36% 7-HB-C 25% and 5-HBB-C 15%

has the following physical properties.

NI: 71.7, Δε: 11.0, Δn: 0.137, η: 26.7, Vth: 1.78.

The physical values of liquid crystal composition (B) consisting ofliquid crystal composition (A) 85% and4″-(5-fluoropentyl)-2,3,5-trifluoro-4-iodobiphenyl (Compound No. 1) 15%,which was obtained in Example 1, were as follows:

NI: 63.5, Δε: 12.5, Δn: 0.138, η: 34.2, Vth: 1.47.

Although composition (B) was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 5

(Using Example 2)

The physical values of liquid crystal composition (C), which wasobtained by using the same method as in Example 4, except that4′-(2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-2′,6′,3-trifluoro-4-chlorobiphenyl (Compound No. 79) whichwas obtained in Example 2 was used instead of4″-(5-fluoropentyl)-2,3,5-trifluoro-4-iodobiphenyl (Compound No. 1) wereas follows: NI: 58.8, Δε: 12.2, Δn: 0.137, η: 35.2, Vth: 1.47.

Although composition (C) was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 6

(Using Example 3)

The physical properties of the liquid crystal composition of CompositionExample 1 were as follows.

NI: 87.6, Δε: 7.9, Δn: 0.158, η: 22.4, Vth: 1.88, P:11.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 7

(Using Example 4)

The physical properties of the liquid crystal composition of CompositionExample 2 were as follows.

NI: 78.4, Δε: 9.3, Δn: 0.153, η: 20.1, Vth: 1.74.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 8

(Using Example 5)

The physical properties of the liquid crystal composition of CompositionExample 3 were as follows.

NI: 86.2, Δε: 30.7, Δn: 0.147, η: 89.2, Vth: 0.90.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 9

(Using Example 6)

The physical properties of the liquid crystal composition of CompositionExample 4 were as follows.

NI: 93.2, Δε: 7.3, Δn: 0.207, η: 38.3, Vth: 1.89.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 10

(Using Example 7)

The physical properties of the liquid crystal composition of CompositionExample 5 were as follows.

NI: 63.2, Δε: 11.9, Δn: 0.120, η: 42.3, Vth: 1.19.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 11

(Using Example 8)

The physical properties of the liquid crystal composition of CompositionExample 6 were as follows.

NI: 66.0, Δε: 9.8, Δn: 0.145, η: 28.0, Vth: 1.28.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 12

(Using Example 9)

The physical properties of the liquid crystal composition of CompositionExample 7 were as follows.

NI: 73.5, Δε: 23.5, Δn: 0.119, η: 37.5, Vth: 0.99.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 13

(Using Example 10)

The physical properties of the liquid crystal composition of CompositionExample 8 were as follows.

NI: 82.5, Δε: 5.7, Δn: 0.117, η: 19.5, Vth: 1.90.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 14

(Using Example 11)

The physical properties of the liquid crystal composition of CompositionExample 9 were as follows.

NI: 79.1, Δε: 19.2, Δn: 0.145, η: 45.5, Vth: 0.88.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 15

(Using Example 12)

The physical properties of the liquid crystal composition of CompositionExample 10 were as follows.

NI: 56.1, Δε: 11.2, Δn: 0.116, η: 32.9, Vth: 1.03.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 16

(Using Example 13)

The physical properties of the liquid crystal composition of CompositionExample 11 were as follows.

NI: 58.7, Δε: 8.5, Δn: 0.157, η: 29.7, Vth: 1.59.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 17

(Using Example 14)

The physical properties of the liquid crystal composition of CompositionExample 12 were as follows.

NI: 90.6, Δε: 9.7, Δn: 0.138, η: 23.9, Vth: 1.36.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 18

(Using Example 15)

The physical properties of the liquid crystal composition of CompositionExample 13 were as follows.

NI: 88.5, Δε: 8.6, Δn: 0.207, η: 19.2, Vth: 1.72.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 19

(Using Example 16)

The physical properties of the liquid crystal composition of CompositionExample 14 were as follows.

NI: 75.4, Δε: 7.3, Δn: 0.128, η: 13.7, Vth: 1.89.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 20

(Using Example 17)

The physical properties of the liquid crystal composition of CompositionExample 15 were as follows.

NI: 85.1, Δε: 7.4, Δn: 0.110, η: 26.3, Vth: 1.84.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 21

(Using Example 18)

The physical properties of the liquid crystal composition of CompositionExample 16 were as follows.

NI: 89.4, Δε: 7.2Δn: 0.092, η: 29.5, Vth: 1.87, P=79.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 22

(Using Example 19)

The physical properties of the liquid crystal composition of CompositionExample 17 were as follows.

NI: 85.9, Δε: 7.1, Δn: 0.111, η: 27.2, Vth: 1.92.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 23

(Using Example 20)

The physical properties of the liquid crystal composition of CompositionExample 18 were as follows.

NI: 71.6, Δε: 8.6, Δn: 0.115, η: 28.3, Vth: 1.45.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 24

(Using Example 21)

The physical properties of the liquid crystal composition of CompositionExample 19 were as follows.

NI: 69.5, Δε: 10.0, Δn: 0.097, η: 27.2, Vth: 1.10, VHR:97.2, 96.2, 94.9.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 25

(Using Example 22)

The physical properties of the liquid crystal composition of CompositionExample 20 were as follows.

NI: 68.2, Δε: 14.2, Δn: 0.093, η: 38.4, Vth: 1.03.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 26

(Using Example 23)

The physical properties of the liquid crystal composition of CompositionExample 21 were as follows.

NI: 88.9, Δε: 4.9, Δn: 0.129, η: 21.7, Vth: 2.32.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 27

(Using Example 24)

The physical properties of the liquid crystal composition of CompositionExample 22 were as follows.

NI: 93.2, Δε: 9.8, Δn: 0.122, η: 37.1, Vth: 1.54.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 28

(Using Example 25)

The physical properties of the liquid crystal composition of CompositionExample 23 were as follows.

NI: 80.0, Δε: 6.2, Δn: 0.095, η: 17.0, Vth: 1.87.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 29

(Using Example 26)

The physical properties of the liquid crystal composition of CompositionExample 24 were as follows.

NI: 69.3, Δε: 9.0, Δn: 0.098, η: 27.9, Vth: 1.53.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 30

(Using Example 27)

The physical properties of the liquid crystal composition of CompositionExample 25 were as follows.

NI: 88.3, Δε: 8.9, Δn: 0.134, η: 36.7, Vth: 1.57, VHR: 97.1, 96.2, 95.0.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 31

(Using Example 28)

The physical properties of the liquid crystal composition of CompositionExample 26 were as follows.

NI: 71.7, Δε: 5.4, Δn: 0.106, η: 22.4, Vth: 1.89.

Although this composition was allowed to stand in a freezer at −20° C.for 60 days, the development of the smectic phase and the precipitationof crystals were not found.

EXAMPLE 32

(Using Example 29)

Liquid crystal composition (D) comprising of the following liquidcrystal compounds of a fluorine type:

7-HB(F,F)-F  6% 3-H2HB(F,F)-F 10% 5-H2HB(F,F)-F 10% 3-HHB(F,F)-F 11%4-HHB(F,F)-F  6% 3-HH2B(F,F)-F 15% 5-HH2B(F,F)-F 12% 3-HBB(F,F)-F  6%5-HBB(F,F)-F  6% 3-HHEB(F,F)-F 10% 4-HHEB(F,F)-F  4% 5-HHEB(F,F)-F  4%

was allowed to stand in a freezer at −20° C., and as a result, theprecipitation of crystals were found at the 9^(th) day.

Liquid crystal composition (E) was obtained by replacing 3HH2B(F,F)-F inthis liquid crystal composition (D) with4′-(2-(2-fluoro-4-(5-fluoropentyl)phenyl)ethyl)-2′,6′,3-trifluoro-4-chlorobiphenyl (Compound No. 79)obtained in Example 4. Although this composition was allowed to stand ina freezer at −20° C. for 34 days, the development of the smectic phaseand the precipitation of crystals were not found.

As described above, by using the compounds of the present invention, itis found that the compatibility is improved at low temperature.

INDUSTRIAL APPLICABILITY

The liquid crystalline compounds of the present invention have a veryhigh voltage holding ratio, very little variation of this propertydepending on temperature and high Δn, and these compounds can be easilymixed with several kinds of liquid crystal materials and have goodcompatibility under a low temperature. Moreover, novel liquidcrystalline compounds having desired physical properties can be providedby suitably selecting the substituent groups and bonding groups of theliquid crystalline compounds of the present invention.

Accordingly, by using the liquid crystalline compounds of the presentinvention as constituents of liquid crystal compositions, novel liquidcrystal compositions having very high voltage holding ratio, very littlevariation of this property depending on temperature, suitable Δn and Δεvalues and excellent stability, and liquid crystal display devicesconstituted by using the liquid crystal compositions can be provided.

What is claimed is:
 1. A liquid crystalline compound represented byformula (1):

wherein R represents an alkyl, alkoxy or alkoxyalkyl group of 2-20carbon atoms, and in each group, and one hydrogen atom is replaced by afluorine atom; X is a halogen atom or —CF₃—, —CF₂H, —CFH₂, —OCF₃, and—OCF₂H; Z₁, Z₂ and Z₃, each independently, represents —(CH₂)₂—,—(CH₂)₄—, —CH₂O—, —OCH₂—, —(CH₂)₃O—, —O(CH₂, ₃— or covalent bond; Y₁,Y₃, Y₅, Y₇, Y₉, Y₁₁, Y₁₃ and Y₁₅ are hydrogen atoms, and Y₂, Y₄, Y₆, Y₈,Y₁₀, Y₁₂, Y₁₄ and Y₁₆ each independently represent hydrogen atoms orfluorine atoms, but at least two of Y₂, Y₄, Y₆, Y₈, Y₁₀, Y₁₂, Y₁₄ andY₁₆ are fluorine atoms; m represents 0 or 1, and any atom constitutingthe compound may be replaced by an isotope thereof.
 2. The liquidcrystalline compound according to claim 1, wherein m is
 0. 3. The liquidcrystalline compound according to claim 1, wherein m is
 1. 4. The liquidcrystalline compound according to claim 2, wherein one hydrogen atom inR is substituted by a fluorine atom.
 5. The liquid crystalline compoundaccording to claim 3, wherein one hydrogen atom in R is substituted by afluorine atom.
 6. A liquid crystal composition, comprising at least oneof liquid crystalline compounds described in claim
 1. 7. A liquidcrystal composition, comprising as the first component thereof at leastone of the compounds described in claim 1, and as the second componentthereof at least one compound selected from the group consisting of thecompounds represented by formula (2), (3) or (4):

wherein R₁ represents an alkyl group of 1-10 carbon atoms, anynonadjacent methylene groups in the alkyl group may be substituted byoxygen atoms or —CH═CH—, and any hydrogen atoms in the alkyl group maybe substituted by fluorine atoms; X₁ represents a fluorine atom, achlorine atom, —OCF₃, —OCF₂H, —CF₃, —CF₂H, —CFH₂, —OCF₂CF₂H or—OCF₂CFHCF₃; L₁ and L₂ independently represent a hydrogen atom or afluorine atom; Z₄ and Z₅ independently represent a 1,2-ethylene group,1,4-butylene group, —COO—, —CF₂O—, —OCF₂—, —CH═CH— or a covalent bond,ring B represents trans-1,4-cyclohexylene, 1,3-dioxane-2,5-diyl or1,4-phenylene whose hydrogen atoms may be substituted by fluorine atoms;ring C represents trans-1,4-cyclohexylene, or 1,4-phenylene whosehydrogen atoms may be substituted by fluorine atoms; and any atomconstituting these compounds may be substituted by its isotope.
 8. Aliquid crystal composition, characterized in that it comprises as afirst component thereof at least one of the compounds described in claim1, and as a second component thereof at least one compound selected fromthe group consisting of the compounds represented by formula (5) or (6):

R₂ and R₃ independently represent an alkyl group of 1-10 carbon atoms,any nonadjacent methylene groups in the alkyl group may be substitutedby oxygen atoms or —CH═CH—, and any hydrogen atoms in the alkyl groupmay be substituted by fluorine atoms, X₂ represents —CN group or—C≡C—CN—; ring D represents trans-1,4-cyclohexylene, 1,4-phenylene,1,3-dioxane-2,5-diyl or pyrimidine-2,5-diyl; ring E representstrans-1,4-cyclohexylene, 1,4-phenylene whose hydrogen atoms may besubstituted by fluorine atoms, or pyrimidine-2,5-diyl; ring F representstrans-1,4-cyclohexylene or 1,4-phenylene; Z₆ represents a 1,2-ethylenegroup, —COO— or a covalent bond; L₃, L₄and L₅ independently represent ahydrogen atom or a fluorine atom; b, c and d independently represent 0or 1; and any atom constituting these compounds may be substituted byits isotope.
 9. A liquid crystal composition, comprising the liquidcrystal composition described in claim 6 and at least one opticallyactive compound.
 10. A liquid crystal display device comprising theliquid crystal composition described in claim
 6. 11. A liquid crystalcomposition comprising as a first component thereof at least onecompound according to claim 1, as a second component thereof at leastone compound selected from the group consisting of the compounds offormula (2), (3), or (4)

wherein R₁ represents an alkyl group of 1-10 carbon atoms, anynonadjacent methylene groups in the alkyl group may be substituted byoxygen atoms or —CH═CH—, and any hydrogen atoms in the alkyl group maybe substituted by fluorine atoms; X₁ represents a fluorine atom, achlorine atom, —OCF₃, —OCF₂H, —CF₃, —CF₂H, —CFH₂, —OCF₂CF₂H or—OCF₂CFHCF₃; L₁ and L₂ independently represent a hydrogen atom or afluorine atom; Z₄ and Z₅ independently represent a 1,2-ethylene group,1,4-butylene group, —COO—, —CF₂O—, —OCF₂—, —CH═CH— or a covalent bond,ring B represents trans-1,4-cyclohexylene, 1,3-dioxane2,5-diyl or1,4-phenylene whose hydrogen atoms may be substituted by fluorine atoms;ring C represents trans-1,4-cyclohexylene, or 1,4-phenylene whosehydrogen atoms may be substituted by fluorine atoms; and any atomconstituting these compounds may be substituted by its isotope; and as athird component thereof at least one compound selected from the groupconsisting of the compounds of formula (7), (8), or (9):

 wherein R₄ and R₅ independently represent an alkyl group of 1-10 carbonatoms, any nonadjacent methylene groups in the alkyl group may besubstituted by oxygen atoms or —CH═CH—, and any hydrogen atoms in thealkyl group may be substituted by fluorine atoms; ring G, ring I andring J independently represent trans-1,4-cyclohexylene,pyrimidine-2,5-diyl, or 1,4-phenylene whose hydrogen atoms may besubstituted by fluorine atoms; Z₇ and Z₈ independently represent —C≡C—,—COO—, —CH₂CH₂—, —CH═CH— or a covalent bond; and any atom constitutingthese compounds may be substituted by its isotope.
 12. A liquid crystalcomposition comprising as a first component thereof at least onecompound according to claim 1, as a second component thereof at leastone compound selected from the group consisting of the compounds offormula (5) or

wherein R₂ and R₃ independently represent an alkyl group of 1-10 carbonatoms, any nonadjacent methylene groups in the alkyl group may besubstituted by oxygen atoms or —CH═CH—, and any hydrogen atoms in thealkyl group may be substituted by fluorine atoms, X₂ represents —CNgroup or —C≡C—CN—; ring D represents trans-1,4-cyclohexylene,1,4,-phenylene, 1,3-dioxane-2,5-diyl or pyrimidine-2,5-diyl; ring Erepresents trans-1,4-cyclohexylene, 1,4-phenylene whose hydrogen atomsmay be substituted by fluorine atoms, or pyrimidine-2,5-diyl; ring Frepresents trans-1,4-cyclohexylene or 1,4-phenylene; Z₆ represents a1,2-ethylene group, —COO— or a covalent bond; L₃, L₄ and L₅independently represent a hydrogen atom or a fluorine atom; b, c and dindependently represent 0 or 1; and any atom constituting thesecompounds may be substituted by its isotope; and as a third componentthe reof at least one compound selected from the group consisting of thecompounds of formula (7), (8), or (9):

 wherein R₄ and R₅ independently represent an alkyl group of carbonatoms of 1-10, any nonadjacent methylene groups in the alkyl group maybe substituted by oxygen atoms or —CH═CH—, and any hydrogen atoms in thealkyl group may be substituted by fluorine atoms; ring G, ring I andring J independently represent trans-1,4-cyclohexylene,pyrimidine-2,5-diyl, or 1,4-phenylene whose hydrogen atoms may besubstituted by fluorine atoms; Z₇ and Z₈ independently represent —C≡C—,—COO—, —CH₂CH₂—, —CH═CH— or a covalent bond; and any atom constitutingthese compounds may be substituted by its isotope.
 13. A liquid crystalcomposition comprising as a first component thereof at least onecompound according to claim 1, as a second component thereof at leastone compound selected from the group consisting of the compounds offormula (2), (3), or (4)

wherein R₁ represents an alkyl group of 1-10 carbon atoms, anynonadjacent methylene groups in the alkyl group may be substituted byoxygen atoms or —CH═CH—, and any hydrogen atoms in the alkyl group maybe substituted by fluorine atoms; X₁ represents a fluorine atom, achlorine atom, —OCF₃, —OCF₂H, —CF₃, —CF₂H, —CFH₂, —OCF₂CF₂H or—OCF₂CFHCF₃; L₁ and L₂ independently represent a hydrogen atom or afluorine atom; Z₄ and Z₅ independently represent a 1,2-ethylene group,1,4-butylene group, —COO—, —CF₂O—, —OCF₂—, —CH═CH— or a covalent bond,ring B represents trans-1,4-cyclohexylene, 1,3-dioxane2,5-diyl or1,4-phenylene whose hydrogen atoms may be substituted by fluorine atoms;ring C represents trans-1,4-cyclohexylene, or 1,4-phenylene whosehydrogen atoms may be substituted by fluorine atoms; and any atomconstituting these compounds may be substituted by its isotope; as athird component thereof at least one compound selected from the groupconsisting of the compounds represented by formula (5) or (6)

 wherein R₂ and R₃ independently represent an alkyl group of 1-10 carbonatoms, any nonadjacent methylene groups in the alkyl group may besubstituted by oxygen atoms or —CH═CH—, and any hydrogen atoms in thealkyl group may be substituted by fluorine atoms, X₂ represents —CNgroup or —C≡C—CN—; ring D represents trans-1,4-cyclohexylene,1,4,-phenylene, 1,3-dioxane-2,5-diyl or pyrimidine-2,5-diyl; ring Erepresents trans-1,4-cyclohexylene, 1,4-phenylene whose hydrogen atomsmay be substituted by fluorine atoms, or pyrimidine-2,5-diyl; ring Frepresents trans-1,4-cyclohexylene or 1,4-phenylene; Z₆ represents a1,2-ethylene group, —COO— or a covalent bond; L₃, L₄ and L₅independently represent a hydrogen atom or a fluorine atom; b, c and dindependently represent 0 or 1; and any atom constituting thesecompounds may be substituted by its isotope and as a fourth componentthereof at least one compound selected from the group consisting of thecompounds of formula (7), (8), or (9):

 wherein R₄ and R₅ independently represent an alkyl group of carbonatoms of 1-10, any nonadjacent methylene groups in the alkyl group maybe substituted by oxygen atoms or —CH═CH—, and any hydrogen atoms in thealkyl group may be substituted by fluorine atoms; ring G, ring I andring J independently represent trans-1,4-cyclohexylene,pyrimidine-2,5-diyl, or 1,4-phenylene whose hydrogen atoms may besubstituted by fluorine atoms; Z₇ and Z₈ independently represent —C≡C—,—COO—, —CH₂CH₂—, —CH═CH— or a covalent bond; and any atom constitutingthese compounds may be substituted by its isotope.